Shader "Simple/CustomWrite"
{
	Properties
	{
		_MainTex("Texture", 2D) = "white" {}
	}
		SubShader
	{
		Tags { "RenderType" = "Opaque" "CustomWrite" = "WaterArea"}
		LOD 100

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			// make fog work
			#pragma multi_compile_fog

			#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				UNITY_FOG_COORDS(1)
				float4 vertex : SV_POSITION;
			};

			sampler2D _MainTex;
			float4 _MainTex_ST;

			v2f vert(appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.uv = TRANSFORM_TEX(v.uv, _MainTex);
				UNITY_TRANSFER_FOG(o,o.vertex);
				return o;
			}

			fixed4 frag(v2f i) : SV_Target
			{
				// sample the texture
				fixed4 col = tex2D(_MainTex, i.uv);
				if (col.a < 0.5)
					discard;
				// apply fog
				return fixed4(1.0,0,0,0);
			}
			ENDCG
		}
	}
		SubShader
			{
				Tags { "RenderType" = "Opaque" "CustomWrite" = "WaterHide"}
				LOD 100
				Pass
				{
					CGPROGRAM
					#pragma vertex vert
					#pragma fragment frag
					// make fog work
					#pragma multi_compile_fog

					#include "UnityCG.cginc"

					struct appdata
					{
						float4 vertex : POSITION;
						float2 uv : TEXCOORD0;
					};

					struct v2f
					{
						float2 uv : TEXCOORD0;
						UNITY_FOG_COORDS(1)
						float4 vertex : SV_POSITION;
					};

					sampler2D _MainTex;
					float4 _MainTex_ST;

					v2f vert(appdata v)
					{
						v2f o;
						o.vertex = UnityObjectToClipPos(v.vertex);
						o.uv = TRANSFORM_TEX(v.uv, _MainTex);
						UNITY_TRANSFER_FOG(o,o.vertex);
						return o;
					}

					fixed4 frag(v2f i) : SV_Target
					{
						// sample the texture
						fixed4 col = tex2D(_MainTex, i.uv);
						if (col.a < 0.5)
							discard;
						// apply fog
						return fixed4(0.0,0,0,0);
					}
					ENDCG
				}
			}

}
